Re: [RE-wrenches] Mounting to SIPs, revisited
Hi Luke Christy, I am wiring a SIP house, and the plans called for hanging a fan on the ceiling. I contacted the manufacturer and they suggested cutting out a rectangular section of the OSB board that extends well beyond the dimension of my ceiling mounted round metal box. Then with a tool called a hot knife, the Styrofoam was melted away. Next we gouged out more Styrofoam, several inches beyond the cut out and slipped some 2x wood blocks into the hole and screwed along the perimeter. Next screw the OSB cutout back in place, and now there is a large area to screw into for your mounting foot. I hope this makes sense. Ralph Pisciotta Willits Electric From: Luke Christy sgsrenewab...@gmail.com To: re-wrenches@lists.re-wrenches.org Sent: Sun, January 17, 2010 8:24:49 PM Subject: [RE-wrenches] Mounting to SIPs, revisited Esteemed Wrenches, We have a PV job in the works that will require mounting racking to several roofs that consist of asphalt shingles laid over SIP panels. The panels are standard 10 nominal thickness, with 9-1/4 of foam sandwiched by 1/2 OSB on each side. The rub is that the underside of the panels will be the finished ceiling (with 5/8 of wood over the OSB). I found a couple of threads in the archives discussing mounting to SIPs, but most comments suggest through-bolting, and that is not an attractive option in this case due to the finished ceiling directly beneath. The roofs in question are triangular in plan, and are fairly small (~ 15' x 15' x 21') Does anyone have experience with mounting directly to the outer skin of a SIP panel? Suggestions on the best way to approach this problem would be appreciated. Thanks in advance. Luke Christy NABCEP Certified PV Installer™: Certification #031409-25 (Luke Christy) CoSEIA Certified PV Installer (Luke Christy) Solar Gain Services, LLC Monte Vista, CO sgsrenewab...@gmail.com 719.588.3044 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] kW/MW v. kWh/MWh
Just a pedagogical note. Since I have been teaching PV Installation now fairly continuously since July of this year. The kW/kWh problem is pretty pervasive: I even slip once and a while. Here is the problem as I see it. Most basic units like mass, distance, energy are simply defined: kilogram, meter and joule. The rates of change are derived: kilometers per hour, meter per second, joule per second (watt). The basic units related to energy (at least within the electrical utility and related fields) are defined first with the rate of change: watts (or joule per second). Then the other quantities are derived from the watt: watt-hour (energy), watts/meter-squared (insolation) and the like. Well that's just a fact, and in my classes I drive that point home early and often - so as to minimize confusion down the road. To enliven things a bit, I also add a little history. In the 18th and 19th centuries, there was a lot of work done trying to understand the nature of and interrelationship between mechanical work, heat and then later electricity. The early work focused on the rate at which work could be done, and concepts like horsepower and later watts were used and compared. An exception to this trend is the unit of heat the British Thermal Unit (BTU) and the rate BTU/hr. Another interesting fact: since the beginning of time (wo)man has invented various units of measure to assist them in carrying out business. The rule of thumb: invent a unit of measure that can be used for the puposes at hand, that is convenient (gives you the level of accuracy you need) and doesn't use zeros (invented in India in 800 AD) or the decimal point (an even later invention). Some examples: (1) A cord of wood (128 cu-ft) is rougly the amount that can fit in the back of a wagon (or large pick up truck). In New England, you can sustainably harvest about 1 cord per acre (if I remember correctly). Whether you cut your own wood or order it from someone else, you would probably think for example in terms of 3 or 4 cords of wood (not 3.5 cords). (2) A bushel is a convenient measure of fruit and vegetables, about a cubic foot. If you needed bake a few of pies and have some left over for eating, you might buy a bushel of apples. (3) A peck is one fourth the volume, maybe more convenient for nuts and berries. (4) A hand (4 inches) is used to measure how tall a horse is. An average horse is about 16 hands; a pony 14 hands or less and a big draft horse could be 19-20 hands. (5) When talking to a customer about their usage per day, the unit of energy kWh is similarly convenient. A small family might use 10 kWh/day and a larger family might use 35 kWh/day. In either case 1 kWh/day one way or another won't make much difference in designing a system that will eliminate their bill. I must admit that with larger commercial accounts we would be looking at numbers like 150 kWh/day and we start using zeros to reflect the fact that we aren't particularly interested in measuring energy usage to a precison of less than 1%. In any event, the kWh is much more convenient than the Joule: there are 3,600,000 Joules in 1 kWh. Of course we could shorten the notation to MJ and now we would have a unit of energy measure that fits the criteria: typical usage and the level of precision doesn't rquire zeros or decimal points. So the small household might use 36 MJ/day and the large household 126 MJ/day. Perhaps one day, we could switch from kWh to MJ! Happy MLK Jr. Day to everyone! NOW what do I do to keep busy? - Peter Peter T. Parrish, Ph.D., President California Solar Engineering, Inc. 820 Cynthia Ave., Los Angeles, CA 90065 CA Lic. 854779, NABCEP Cert. 031806-26 mailto:peter.parr...@calsolareng.com peter.parr...@calsolareng.com Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Dorsett Sent: Sunday, January 17, 2010 4:38 PM To: RE-wrenches; Dan Fink Subject: Re: [RE-wrenches] kW/MW v. kWh/MWh But you know they keep talking about the potential contribution that plug-in hybrids might have for storing energy for utility support. Most of our systems have hugely larger capacity than current Prius'. And I suspect that many RE system owners will want some backup, especially if they are compensated for installing it. Bill Dorsett SunwrightS 1715 Leavenworth Manhattan, KS 66502 Home/Office 785/539=1956 Cell 785/564-2583 wmdors...@sbcglobal.net See Amory Lovins July 08 on Charlie Rose http://www.charlierose.com/guests/amory-lovins --- On Sat, 1/16/10, Dan Fink dan...@hughes.net wrote: From: Dan Fink dan...@hughes.net Subject: Re: [RE-wrenches] kW/MW v. kWh/MWh To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Saturday, January 16, 2010, 8:51 PM Hello Marco. No d'oh! Your assessment is correct; you can't store kilowatts of power, you *can* store kilowatt hours
Re: [RE-wrenches] EnPhase/Racking Best Fit
I'll second that! We had good luck with the little clips for the Enphase, but there's a lot of opportunity for having to do a lot of work over again if anything goes wrong. This is my disappointment with the Clicksys in general. In my opinion, the genious of the SolarMount is the T-bolt that allows you to install top clamps as you go instead of having to slide everything down from the end of the rail. Clicksys does away with this. When you add in the Enphase to the Clicksys, you have a very non-flexible installation. All the top clamps have to be in place before the inverters are installed. If you miss or break a clamp you have to take all your inverters off and slide all the clips off to get a new one in place. Also on my list of why I'm underwhelmed by Clicksys is that with our 25lb snow load here you need an attachment every 24. In my mind this makes them only practical on standing seam roof. I'm a big fan of Unirac, but I think they missed on this one. Dana Dana Brandt Ecotech Energy Systems, LLC www.ecotechenergy.com d...@ecotechenergy.com 360.510.0433 On Sat, Jan 16, 2010 at 3:06 PM, solarepiph...@gmail.com wrote: Erika, I can tell you from experience that the Unirac Clicksys is NOT an ideal candidate for Enphase applications. The reason is that if you have a problem with a mounting clip that galls up or breaks, you have to disassemble the entire racks worth of sliders and microinverters in order to replace. The only way to slide on a replacement is from the end of the rail or a splice point. Really a pain. Take care, Eric Thomas Founder Solar Epiphany LLC Seattle Sent from my Verizon Wireless BlackBerry -Original Message- From: re-wrenches-requ...@lists.re-wrenches.org Date: Sat, 16 Jan 2010 02:04:07 To: re-wrenches@lists.re-wrenches.org Subject: RE-wrenches Digest, Vol 3, Issue 63 Send RE-wrenches mailing list submissions to re-wrenches@lists.re-wrenches.org To subscribe or unsubscribe via the World Wide Web, visit http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org or, via email, send a message with subject or body 'help' to re-wrenches-requ...@lists.re-wrenches.org You can reach the person managing the list at re-wrenches-ow...@lists.re-wrenches.org When replying, please edit your Subject line so it is more specific than Re: Contents of RE-wrenches digest... When responding to posts within the Digest, be sure to restore the Subject: line to the original, and please edit out any extraneous lines from the quoted message. Today's Topics: 1. Re: trapeziod modules (William Dorsett) 2. Re: enphase and racks (frenergy) 3. Re: discharging Rolls batteries (Bruce Geddes) -- Message: 1 Date: Fri, 15 Jan 2010 20:58:29 -0800 (PST) From: William Dorsett wmdors...@sbcglobal.net To: RE-wrenches re-wrenches@lists.re-wrenches.org, jry...@netscape.com Subject: Re: [RE-wrenches] trapeziod modules Message-ID: 691869.43614...@web81907.mail.mud.yahoo.com Content-Type: text/plain; charset=iso-8859-1 Jeff, Sharp is the only manufacturer I know of that puts out at least triangular modules that can come close to forming a trapezoid. Bill Dorsett SunwrightS 1715 Leavenworth Manhattan, KS 66502 Home/Office 785/539=1956 Cell 785/564-2583 wmdors...@sbcglobal.net See Amory Lovins July 08 on Charlie Rose http://www.charlierose.com/guests/amory-lovins --- On Fri, 1/15/10, Jeff Yago jry...@netscape.com wrote: From: Jeff Yago jry...@netscape.com Subject: Re: [RE-wrenches] trapeziod modules To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, January 15, 2010, 9:27 PM I have a demonstration project that will require only a handfull of modules that need to form a round circle when grouped together.? I need a complete circle that will have a combined output of 400 to 600 watts, depending on module size.? I have seen several large modules this shape in recent articles about solar sun-flower shaped street lighting, but I do not need anything that large and its not for a street light application.? Anybody know a supplier that will sell in small quantities? Thanks, Jeff Yago jry...@netscape.com _ Netscape.? Just the Net You Need. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -- next part -- An HTML attachment was scrubbed... URL:
[RE-wrenches] SIPs
We did a project with SIPs roof and the owner /builder theoretically contacted SIPS and they had them cut out and lay in 2 x 10s as a backing with a bonding agent to the foam [Not known what this was] and then high temp ice and water shield and then the synthetic recycled roof material. Has anyone else heard of this procedure? If so do you know what the bonding agent would be? Dana Orzel Great Solar Works, Inc www.solarwork.com E - d...@solarwork.com V - 970.626.5253 F - 970.626.4140 C - 970.209.4076 I will be the shift in how the world uses power! - Dana Orzel From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of RALPH PISCIOTTA Sent: Monday, January 18, 2010 8:34 AM To: RE-wrenches Subject: Re: [RE-wrenches] Mounting to SIPs, revisited Hi Luke Christy, I am wiring a SIP house, and the plans called for hanging a fan on the ceiling. I contacted the manufacturer and they suggested cutting out a rectangular section of the OSB board that extends well beyond the dimension of my ceiling mounted round metal box. Then with a tool called a hot knife, the Styrofoam was melted away. Next we gouged out more Styrofoam, several inches beyond the cut out and slipped some 2x wood blocks into the hole and screwed along the perimeter. Next screw the OSB cutout back in place, and now there is a large area to screw into for your mounting foot. I hope this makes sense. Ralph Pisciotta Willits Electric _ From: Luke Christy sgsrenewab...@gmail.com To: re-wrenches@lists.re-wrenches.org Sent: Sun, January 17, 2010 8:24:49 PM Subject: [RE-wrenches] Mounting to SIPs, revisited Esteemed Wrenches, We have a PV job in the works that will require mounting racking to several roofs that consist of asphalt shingles laid over SIP panels. The panels are standard 10 nominal thickness, with 9-1/4 of foam sandwiched by 1/2 OSB on each side. The rub is that the underside of the panels will be the finished ceiling (with 5/8 of wood over the OSB). I found a couple of threads in the archives discussing mounting to SIPs, but most comments suggest through-bolting, and that is not an attractive option in this case due to the finished ceiling directly beneath. The roofs in question are triangular in plan, and are fairly small (~ 15' x 15' x 21') Does anyone have experience with mounting directly to the outer skin of a SIP panel? Suggestions on the best way to approach this problem would be appreciated. Thanks in advance. Luke Christy NABCEP Certified PV Installer™: Certification #031409-25 (Luke Christy) CoSEIA Certified PV Installer (Luke Christy) Solar Gain Services, LLC Monte Vista, CO sgsrenewab...@gmail.com 719.588.3044 No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.725 / Virus Database: 270.14.148/2629 - Release Date: 01/17/10 12:35:00 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Mounting to SIPs, revisited
Alan, Thanks for the correction, I did in fact use the blue 'roof grip screws' with neopreme washers provided by DPW for use in OSB. I better go chug more Ginko. Bill Feather River Solar Electric 4291 Nelson St. Taylorsville, CA 95983 - Original Message - From: Allan Sindelar To: RE-wrenches Sent: Sunday, January 17, 2010 10:46 PM Subject: Re: [RE-wrenches] Mounting to SIPs, revisited Just a note of caution here: Tech screws are Tek screws, which are essentially a sheet metal thread following a pilot drill point, on a hardened shank. They are intended for mounting only into metal, not wood; the drill point isn't designed to self-pilot into wood, and the drill section is too large in diameter for wood. ![endif]-- Allan Sindelar al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer EE98J Journeyman Electrician Positive Energy, Inc. 3201 Calle Marie Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com frenergy wrote: Luke, Direct Power and Water has an optional mounting foot with five holes in it for what I think Jeff Randall there referred to as 'Tech' screws to use in the field between rafters. They are referred to as 'easy feet'. It is designed to only attach into the roof decking, which I'm pretty sure only required 1/2 OSB. He claims the same or better pullout values as one lag per regular foot...there may also be tighter spacing involved for the feet. The choices are 1 1/2 or 3 long, has a self tapping point so no pre-drill. Add some of the peel and stick mastic and it's a fast install. Bill Feather River Solar Electric 4291 Nelson St. Taylorsville, CA 95983 - Original Message - From: Luke Christy To: re-wrenches@lists.re-wrenches.org Sent: Sunday, January 17, 2010 8:24 PM Subject: [RE-wrenches] Mounting to SIPs, revisited Esteemed Wrenches, We have a PV job in the works that will require mounting racking to several roofs that consist of asphalt shingles laid over SIP panels. The panels are standard 10 nominal thickness, with 9-1/4 of foam sandwiched by 1/2 OSB on each side. The rub is that the underside of the panels will be the finished ceiling (with 5/8 of wood over the OSB). I found a couple of threads in the archives discussing mounting to SIPs, but most comments suggest through-bolting, and that is not an attractive option in this case due to the finished ceiling directly beneath. The roofs in question are triangular in plan, and are fairly small (~ 15' x 15' x 21') Does anyone have experience with mounting directly to the outer skin of a SIP panel? Suggestions on the best way to approach this problem would be appreciated. Thanks in advance. Luke Christy NABCEP Certified PV Installer™: Certification #031409-25 (Luke Christy) CoSEIA Certified PV Installer (Luke Christy) Solar Gain Services, LLC Monte Vista, CO sgsrenewab...@gmail.com 719.588.3044 -- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.432 / Virus Database: 270.14.147/2628 - Release Date: 01/17/10 07:35:00 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios:
[RE-wrenches] Walt Ratterman
I heard that fellow Wrench Walt Ratterman is MIA in Haiti. Anyone have any news? marco ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Mounting to SIPs, revisited
Good Folks,
We did a job on Hunter panels - which are even
worse than SIPS because they have no lumber at
the edges in the rafter orientation like SIPS do.
We used the large surface area mounts like
Ecofasten or Rapid Foot thare intended for metal
roofs and instead modified them to work with SIPS
by changing the screw lengths and patterns.
We used EcoFasten's products:
http://www.ecofastensolar.com/our-products/eco-fasten
You could also use UNIRACs rapid foot or
equivalent. We then customized the screw pattern
such that every other screw was a short or long
one - the short ones going into the top sheathing
and the long ones going into the base sheathing
(and/or rafters if you need to) that the Hunter
or SIP sits on.
We also then made sure to install long screws
that go down into the lower sheathing underneath
the steel plate of the ecofasten - that way the
compression force is transferred below. And then
more long screws aboveand through the plate. You
can even plan to hit rafters below if you really
plan ahead or do it during new construction.
You have to do the calcs on what the foam can
handle for psi and what uplift you need, etc.
Bring in an engineer on this.
We used 30' centers - it's very expensive - but
the idea is to distribute the weight - kind of
like an S5 approach. We had an engineer do the
calcs.
Best of luck!
Send $ to Haiti,
Jeff C.
Alan,
Thanks for the correction, I did in fact
use the blue 'roof grip screws' with neopreme
washers provided by DPW for use in OSB. I
better go chug more Ginko.
Bill
Feather River Solar Electric
4291 Nelson St.
Taylorsville, CA 95983
- Original Message -
From: mailto:al...@positiveenergysolar.comAllan Sindelar
To: mailto:re-wrenches@lists.re-wrenches.orgRE-wrenches
Sent: Sunday, January 17, 2010 10:46 PM
Subject: Re: [RE-wrenches] Mounting to SIPs, revisited
Just a note of caution here: Tech screws are
Tek screws, which are essentially a sheet
metal thread following a pilot drill point, on a
hardened shank. They are intended for mounting
only into metal, not wood; the drill point isn't
designed to self-pilot into wood, and the drill
section is too large in diameter for wood.
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Allan Sindelar
mailto:al...@positiveenergysolar.comal...@positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
http://www.positiveenergysolar.com/www.positiveenergysolar.com
frenergy wrote:
Luke,
Direct Power and Water has an optional
mounting foot with five holes in it for what I
think Jeff Randall there referred to as 'Tech'
screws to use in the field between rafters. They
are referred to as 'easy feet'. It is designed
to only attach into the roof decking, which I'm
pretty sure only required 1/2 OSB. He claims
the same or better pullout values as one lag per
regular foot...there may also be tighter spacing
involved for the feet. The choices are 1 1/2
or 3 long, has a self tapping point so no
pre-drill. Add some of the peel and stick
mastic and it's a fast install.
Bill
Feather River Solar Electric
4291 Nelson St.
Taylorsville, CA 95983
- Original Message -
From: mailto:sgsrenewab...@gmail.comLuke Christy
To:
mailto:re-wrenches@lists.re-wrenches.orgre-wrenches@lists.re-wrenches.org
Sent: Sunday, January 17, 2010 8:24 PM
Subject: [RE-wrenches] Mounting to SIPs, revisited
Esteemed Wrenches,
We have a PV job in the works that will require
mounting racking to several roofs that consist
of asphalt shingles laid over SIP panels. The
panels are standard 10 nominal thickness, with
9-1/4 of foam sandwiched by 1/2 OSB on each
side. The rub is that the underside of the
panels will be the finished ceiling (with 5/8
of wood over the OSB).
I found a couple of threads in the archives
discussing mounting to SIPs, but most comments
suggest through-bolting, and that is not an
attractive option in this case due to the
Re: [RE-wrenches] Walt Ratterman
Walt is still believed to be buried in the Hotel Montana. Lots of rescue teams on site and people still being found alive. A team of Walt's friends and associates has now also arrived on site. Hope is still very much alive. There is a facebook page devoted to the rescue - there is a tremendous network of people hoping and praying and supporting the process. http://www.facebook.com/pages/Walt-Ratterman-Haiti-Mission Jeff Lahl | Project Director Solar Electric Light Fund | http://www.self.org/ www.self.org p 808-874-5706 f 808-874-5706 energy is a human rightT https://www.givedirect.org/give/givefrm.asp?Action=GCCID=868AVS=OFF Change a life. Change the world From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Marco Mangelsdorf Sent: Monday, January 18, 2010 9:19 AM To: 'RE-wrenches' Subject: [RE-wrenches] Walt Ratterman I heard that fellow Wrench Walt Ratterman is MIA in Haiti. Anyone have any news? marco ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Capacity loss due to rapid discharge
Hugh, You may be interested in this article "A critical review of using the Peukert equation for determining the remaining capacity of lead-acid and lithium-ion batteries" by Dennis Doerffel and Suleiman Abu Sharkh from the School of Engineering Sciences, University of Southampton. It is available from http://www.sciencedirect.com/science for a small fee. If the link does not work, just search for the lead author's last name. The authors describe testing lead acid batteries at high rates of discharge from fully discharged down to the point that the terminal voltage is 10.0 volts. After letting the batteries rest, they continued to discharge further at a lower rate until the terminal voltage was again 10.0 volts. Results were compared to discharging at the slow rate only. The total amphours delivered when a low discharge rate follows a high discharge were less by 5 to 10%. With 10% associated with a C2 and C/20 discharge of a 17 AH battery and 5% associated with a C/1.2 and C/13 discharge of a 65 ah battery. In short, the capacity loss indicated by Peukert only applies to a continuous discharge rate. When a slow discharge follows a rapid discharge, the total number of amphours delivered is almost the same (just 5 to 10% less) as if the discharge happened at entirely at the slow rate. If you were estimating how far your electric car would travel, that 5 or 10% may be critical. For the rates of discharge and depths of discharge normally used for off-grid homes the "lost" capacity is probably even less. Kent Osterberg Blue Mountain Solar, Inc. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] EnPhase/Racking Best Fit
I was involved in Beta Tests for Clicksys, and had to deal with mounting Enphase with the Clicksys Beam, which was a pain. In the end, we decided not to use the product. When you lay out the rails, the rail splices can't be on top of the feet? The amount of planning and layout makes it not ideal. I second the other comments about the clips, too. Nick Soleil Project Manager Advanced Alternative Energy Solutions, LLC PO Box 657 Petaluma, CA 94953 Cell: 707-321-2937 Office: 707-789-9537 Fax:707-769-9037 From: Dana Brandt d...@ecotechenergy.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Sent: Mon, January 18, 2010 10:06:18 AM Subject: Re: [RE-wrenches] EnPhase/Racking Best Fit I'll second that! We had good luck with the little clips for the Enphase, but there's a lot of opportunity for having to do a lot of work over again if anything goes wrong. This is my disappointment with the Clicksys in general. In my opinion, the genious of the SolarMount is the T-bolt that allows you to install top clamps as you go instead of having to slide everything down from the end of the rail. Clicksys does away with this. When you add in the Enphase to the Clicksys, you have a very non-flexible installation. All the top clamps have to be in place before the inverters are installed. If you miss or break a clamp you have to take all your inverters off and slide all the clips off to get a new one in place. Also on my list of why I'm underwhelmed by Clicksys is that with our 25lb snow load here you need an attachment every 24. In my mind this makes them only practical on standing seam roof. I'm a big fan of Unirac, but I think they missed on this one. Dana Dana Brandt Ecotech Energy Systems, LLC www.ecotechenergy.com d...@ecotechenergy.com 360.510.0433 On Sat, Jan 16, 2010 at 3:06 PM, solarepiph...@gmail.com wrote: Erika, I can tell you from experience that the Unirac Clicksys is NOT an ideal candidate for Enphase applications. The reason is that if you have a problem with a mounting clip that galls up or breaks, you have to disassemble the entire racks worth of sliders and microinverters in order to replace. The only way to slide on a replacement is from the end of the rail or a splice point. Really a pain. Take care, Eric Thomas Founder Solar Epiphany LLC Seattle Sent from my Verizon Wireless BlackBerry -Original Message- From: re-wrenches-requ...@lists.re-wrenches.org Date: Sat, 16 Jan 2010 02:04:07 To: re-wrenches@lists.re-wrenches.org Subject: RE-wrenches Digest, Vol 3, Issue 63 Send RE-wrenches mailing list submissions to re-wrenches@lists.re-wrenches.org To subscribe or unsubscribe via the World Wide Web, visit http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org or, via email, send a message with subject or body 'help' to re-wrenches-requ...@lists.re-wrenches.org You can reach the person managing the list at re-wrenches-ow...@lists.re-wrenches.org When replying, please edit your Subject line so it is more specific than Re: Contents of RE-wrenches digest... When responding to posts within the Digest, be sure to restore the Subject: line to the original, and please edit out any extraneous lines from the quoted message. Today's Topics: 1. Re: trapeziod modules (William Dorsett) 2. Re: enphase and racks (frenergy) 3. Re: discharging Rolls batteries (Bruce Geddes) -- Message: 1 Date: Fri, 15 Jan 2010 20:58:29 -0800 (PST) From: William Dorsett wmdors...@sbcglobal.net To: RE-wrenches re-wrenches@lists.re-wrenches.org, jry...@netscape.com Subject: Re: [RE-wrenches] trapeziod modules Message-ID: 691869.43614...@web81907.mail.mud.yahoo.com Content-Type: text/plain; charset=iso-8859-1 Jeff, Sharp is the only manufacturer I know of that puts out at least triangular modules that can come close to forming a trapezoid. Bill Dorsett SunwrightS 1715 Leavenworth Manhattan, KS 66502 Home/Office 785/539=1956 Cell 785/564-2583 wmdors...@sbcglobal.net See Amory Lovins July 08 on Charlie Rose http://www.charlierose.com/guests/amory-lovins --- On Fri, 1/15/10, Jeff Yago jry...@netscape.com wrote: From: Jeff Yago jry...@netscape.com Subject: Re: [RE-wrenches] trapeziod modules To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, January 15, 2010, 9:27 PM I have a demonstration project that will require only a handfull of modules that need to form a round circle when grouped together.? I need a complete circle that will have a combined output of 400 to 600 watts, depending on module size.? I have seen several large modules this shape in recent articles about solar sun-flower shaped street lighting, but I do not need anything that large and its not for a street light application.? Anybody know a supplier that will sell in small quantities? Thanks, Jeff Yago
Re: [RE-wrenches] EnPhase/Racking Best Fit
Friends: The T-bolts scare me. If you get them rotated fully, there is but a little nib on each end of the T that constitutes your entire hold down strength. Fail to rotate them fully and your hold down strength is compromised. DPW has a new approach I inspected at the SPI: The hold down clip is indexed to the T-bolt. The T bolt must be fully rotated before the clip can be lowered between the modules. I find this way more-better. Another advantage to DPW clips: they require 1/4 spacing instead of 1. I prefer Unirac rail -- I might try substituting DPW hardware into Unirac rail. Has anyone tried this?. William Miller At 10:12 AM 1/18/2010, you wrote: I'll second that! We had good luck with the little clips for the Enphase, but there's a lot of opportunity for having to do a lot of work over again if anything goes wrong. This is my disappointment with the Clicksys in general. In my opinion, the genious of the SolarMount is the T-bolt that allows you to install top clamps as you go instead of having to slide everything down from the end of the rail. Clicksys does away with this. When you add in the Enphase to the Clicksys, you have a very non-flexible installation. All the top clamps have to be in place before the inverters are installed. If you miss or break a clamp you have to take all your inverters off and slide all the clips off to get a new one in place. Also on my list of why I'm underwhelmed by Clicksys is that with our 25lb snow load here you need an attachment every 24. In my mind this makes them only practical on standing seam roof. I'm a big fan of Unirac, but I think they missed on this one. Dana ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
